The pushrods are available in all kinds of lengths. Figure out what you need and then find the closest one they already have in stock. 99% of the time they are an off the shelf item.
By the way, every hyd. lifter I have ever had instructions for says to not fill them with oil. Doing that makes them nearly impossible to accurately adjust static/cold.
- Good to hear that they're likely to stock pushrods in the length we'll need. I was worrying that we could be waiting for weeks.
All of the threads I've been reading lately agree with you about setting the lash with dry hydraulic lifters. - But I have seen some reliable sources that do say that as long as a person uses the vertical movement means of feeling for zero lash - you still should be accurate.